fix(deps): pin dependency simple-git to 3.17.0

Author: renovate[bot]

packages/changesets-renovate/package.json

@@ -25,6 +25,6 @@
   },
   "license": "MIT",
   "dependencies": {
-    "simple-git": "^3.17.0"
+    "simple-git": "3.17.0"
   }
 }